This invention relates to lighting systems for motor cycles or similar two-wheeled vehicles. My earlier No. Pat. No. 3,939,339 referred to above describes a system for the automatic correction of the orientation of the beam of light of a motor-cycle or similar two-wheeled vehicle headlamp comprising means for turning at least the optical system of the headlamp about an axis of rotation adjacent the optical axis, and a transducer detector system adapted to detect the angle of inclination of the vehicle while turning, said means for turning the optical system of the headlamp being controlled by the transducer detector in such a manner that a compensating orientation variation is applied to the headlamp beam when the vehicle makes a turn.
There are described in the said earlier patent some electro-mechanical transducer detector systems which operate by means of the displacement against a bias of a mass or weight due to centrifugal force resulting from turning of the vehicle. Such systems operate satisfactorily but there is a desire to improve the reliability and accuracy of detection. It is difficult to ensure that the weight moves smoothly and reliably on turning and to ensure that it always moves by the same amount on repeated identical turns. Also the force on the weight is only indirectly related to the angle of inclination of the vehicle.